Power driven rotary surfacing machine for concrete and the like



' Dec. 2, 1958 D. R. TALBOTT 2,862,427

POWER DRIVEN ROTARY SURFACING MACHINE FOR CONCRETE AND THE LIKE Filed March 28, 1956 INVENTOR 0,4100 R. TALBOT? Jou/ymw 9 Fi ,3 7 BY I ATTORNEYS 1 aggregate of the mix,

POWER DRI VEN ROTARY SURFACING MACHINE FOR CONCRETE AND THE LIKE David R. Talbott, Annapolis, Md.

Application March 28, 1956, Serial No. 574,468

7 Claims. (Cl. 94-45) This invention relates to power-driven surfacing implements and more particularly to improved rotary powerdriven apparatus which is particularly though not exclusively useful for floating concrete.

Floating as used herein refers to the art of surface treating newly laid, partially-set concrete through the action of wiping-elements known as floats which have the property of drawing entrained water and fines of the concrete mix to the surface of the partially set concrete for the purpose of covering or surfacing over the heavier Floating has been standard procedure for many years in the laying of concrete in roadways, pavements, floors and the like, and formerly floating was accomplished by rubbing elements or floats attached to long handles and which were manually scraped or rubbed across the surface of the damp concrete, During United States Patent the past decade or so there have been developed power- 7 driven rotary floating machines having a progressive circular wiping engagement over the surface of the concrete and it is an object of the present invention to provide an improved floating machine of this general type.

The rotary power-driven machines of the type referred to have heretofore relied on the use of floats comprising radial, flat, plate-like devices which sweep over the surface of the concrete and perform the floating operation. An object of the present invention is to substitute for the floats of the prior art, roller devices having compound rotary motion to provide a more efficacious floating and concrete surfacing action than has been possible with the machines of the prior art.

A more specific object of the invention is to provide a power-driven rotary type floating machine utilizing roller floats wherein the floats serve not only to float the concrete but serve simultaneously to exert a smoothing action on the surface of the concrete in a novel manner not heretofore contemplated in the art of floating concrete.

Yet another object of the invention is the provision of a surfacing machine of the type described wherein roller v floats of one material may be quickly and easily replaced by floats or implements of another material or structure or for a different purpose.

Other objects and their attendant advantages will be come apparent as the following detailed description is read in conjunction with the accompanying drawings wherein:

Fig. l is a perspective view of a power-driven rotary concrete finishing machine embodying the present invention;

Fig. 2 is a vertical section of a part of the machine of Fig. 1 taken substantially on the line 22 of Fig. 1; and

Fig. 3 is a diagrammatic view illustrating the effect of the compound rotary motion imparted to the roller by the machine of the present invention.

Referring now to the drawings, the rotary floating machine of Fig. 1 comprises a rotary base 10 from which radiate a plurality of rotatable rollers 12, 13, and 14 surrounded by a fixed guard ring 16 secured by suitablestruts 17 to a relatively stationary portion of the machine as 'ice I illustrated. Located in axial relationship to the revolvable base 10 is an upper relatively stationary gear housing 18 surmounted by a driving motor 20. The motor shown in Fig. 1 is a conventional internal combustion type, and there may be substituted for it a conventional electric motor though for many uses the internal combustion engine is preferable since it imparts to the rollers .a rapid vibratory motion which is beneficial in tamping the concrete and driving more readily to the surface thereof water entrained therein. A driving pulley 22 of the motor 20, of whatever type, is connected by a l -belt with a driven pulley 24 of the gear driving mechanism within the housing 18. A handle 26 extends upwardly and radially from the housing 18 for controlling and guiding the machine.

The power transmission and driving means for the rotatable parts of the machine of the invention are conventional and may be generally similar to the driving means disclosed in the patent to McCrery No. 2,689,507 to which reference is, made for a general description. Briefly, however, the driving means comprises the worm 23, illustrated in Fig. 2, which is integrally connected for rotation to the driven pulley 24. The worm engages a worm gear 30 which is press fitted or otherwise secured to the upper end of. a sleeve 32 which extends downwardly from the housing 18 into the revolvable base 10. Secured to the lower end of the sleeve as by set screws 33, is a horizontal plate 34 carrying suitable bearing members 36 for rotatably supporting the inner ends of shafts 37 which are connected to the rollers 12 of the invention in a manner to be later described in detail.

Surrounding sleeve 32 and press fitted thereover or otherwise connected thereto is an outer sleeve 40 whose lower end terminatesin integral radial arms of a spider 42 which are bolted or otherwise secured to the upper surface of the revolvable base member 10. The outer sleeve 40 projects into the gear box 18 to just beneath the worm wheel and is provided on its exterior with a bearing surface engaged by a suitable bearing 44 interposed between the sleeve 40 and the central opening through the bottom of the gear box. Any other type packing or gland could be substituted for the bearing 44. The gear box 18 may nection by screws 53' to the upper surface of the closure. member 46, extends axially downwardly through the neck 48 and through the inner shaft 32 into the interior of the revolvable base member andhas connected to the lower end thereof a horizontal ring gear 56 which is preferably of the bevel type whose teeth are engaged by beveled pinion gears 58 securely attached to the shafts 37 of the rollers 12, 14, and of considerably less diameter than the ring gear, with the ring gear being disposed in-a plane below the horizontal axes of the pinions and rollers to impart the desired movement to the rollers as will become fully apparent.

From the description so far, it should be apparent that when the machine is in operation, the gear box 18, shaft 52, and ring gear 56 are maintained relatively stationary whereas worm gear 30, inner and outer sleeves 32, 40,

plate 34 and hence shafts 36 and hollers 12, and base 10 are all rotated simultaneously and as a unit about the vertical axis of the stationary shaft 52; that is to say,

an orbital movement is imparted to the rollers about the vertical axis of the machine. Simultaneously with this orbital movement, the shafts 37, due to the engagement of their pinions 58 with the ring gear 56, are rotated at a greater speedltharr the orbitalispeed of rotation but in the same directionasthis orbitalrotation; that is to" say, the rollers 12 rotate in the same direction-as they would were they freely mounted to roll if plate 34 were turned without any intervention of the ring and pinion gears. With these latter members, however, juxtaposed with respect to each other as shown and described, it will'be apparent that the rollers when moved orbitally must rotate at a greater rate than their natural rolling speed but in the same direction thereof so that there is provide a relative movement in one direction (i. c., in the direction of orbital movement) between the points of contact of the roller with the surface of the concrete.

Fig. 3 is intended to illustrate the effects achieved by the machine of the invention. The arrow 61 represents the forward or orbital movement of the rollers 14, the arrow 65 represents the forwardly skidding motion of the rollers as they rotate about their own axes and the arrow 57 represents a vibratory action which may result partly from the action of an internal'combustion engine if' this is used and also from the bumping of the rollers over the coarse aggregate which would be uniformly dispersed throughout the concrete mix with some naturally residing uniformly in and projecting slightly above the surface of the untreated concrete. An additional vibratory action is thought to be derived as a result of the forward-skidding relationship of the rollers with respect to the concrete. That is to say, with the rollers unable to rotate orbitally about the vertical axis at the speed with which they are driven about their own axes, the rollers are thought to have an inherent tendency to bounce due to the aforedescribed forwardly rolling and skidding action. In any event, vibratory action, whatever the cause, occurs and this action in combination With the rolling-skidding action drives the coarse aggregate beneath the surface of the concrete and forces the fines and whatever water there may be to the surface. In Fig. 3 the surfaced fines are represented by the numeral 59 whereas the numeral 63 represents exaggeratedly the coarse material directly in front of the rollers which would be covered by the fines forced to the surface behind the rollers. Since the rollers rotate in the same direction as their orbital movement, they exert a continuous and progressive smoothing action on the concrete surface without an abraiding action or tendency to dig into the concrete.

It is well known in the art of floating concrete, that varying conditions, e. g., atmospheric conditions, concrete mix, rate of drying, etc., require the use of heats of different materials or sizes suitable for the prevailing conditions. A steel float might be suitable on one occasion whereas a wood'float would be suitable on another. Furthermore, during the course of a single floating operation, conditions may be initially misjudged or the prevailing condition may change so that floats must be changed and where this must be done ona single job where the concrete may be setting at a rapid rate, the floats must be changeable quickly and easily. The pres ent invention provides for this and with reference to Fig. 2, it will be. observed that the outer ends 6d of the shafts 37 have a square cross-section for engagement with a square axial hole or socket in the rollers. It is contemplated that the shaft 69 and hole could be splined or otherwise provided with guide or locking means to achieve the same results as the square shaft and hole but the latter are preferable from the economy of manufacture point of view. Adjacent the inner end of the square section of each shaft. 37 there is mounted thereon an integral collar 62 adapted to have fitted thereover a flanged cup-shaped clamping member 64 whose flange may be screwed to the exterior surface of the end of the floats by suitable machine screws engageable with registering previously threaded holes in the float end. With the described arrangement, it will be apparent that the square end of the shaft need project only partially along the length of the rollers without projecting through the outer ends thereof to receive a nut as might otherwise be contemplated for mounting rollers for other uses. Thus rollers of different lengths can be readily substituted for any which may previously have been installed on the machine. For rollers which would extend beyond an already installed guard 16, it is contemplated that the guard already on themachine could be readily removed and another of appropriate size substituted therefor.

To those skilled in the art it would be apparent that with only slight modifications the central shaft 52 and its attached ring gear could be disconnected from the stationary gear box 18 and locked to the rotatable sleeve 32 and 49 for rotation therewith; This could be accomplished, for example, by removing the screws 53' from the flange 53 of the shaft and substituting elongated set screws for the screws 33 attaching the plate 34 to sleeve 32. The substituted set screws could project through the sleeve 32 to engage with suitable locating holes spaced about the periphery of the shaft in registering relationship With the substituted set screws. Such holes are indi cated in the shaft at 72 and with set screws engaged therein and shaft 52 disconnected from gear box 18 it will be apparent that said shaft will rotate as a unit with the other elements rotated through the action of the worm 28. Under these conditions, the pinion 58 will be locked with respect to the gear 56 so that there can be no axial rotation of the shafts 37 and anything carried thereon. Thus rollers would merely wipe along the surface without rotating with respect thereto and, if this were desirable for some particular surfacing operation, a new point of contact of the rollers with the surface could be brought into position by merely backing off the set screws and rotating shaft 52 with respect to base 10 to align another set of locating holes with the set screws substituted at 33. This action would have the effect of rotating the pinions' a partial revolution so that another point of contact of the rollers would engage the surface.

It follows from the foregoing that instead of utilizing rollers, these members could be entirely replaced, as for example, by blades similar to those illustrated in the patent to McCrery No. 2,594,331. It will be observed that if blades of this type are provided with sockets adapted to receive the shaft ends 66 of the present invention, the angle of tilt of the blades for various surface treating operations could be readily controlled through the device of the set screw and locking means described above for the partial rotation of rollers locked against axial rotation. The matters set forth in the foregoing paragraph are by way of example of the versatility of the machine of the present invention.

It is believed that from the foregoing description the operation of the machine of the present invention is obvious. It should of course be understood that the entire machine structure is movable bodily about the surface by pushing slightly up or down on the handle 26 which causes the machine to move in a similar fashion as any rotary polishing, sanding or floating machine. The use of rollers having a combined orbital motion and axial rotation in the same direction but at a greater speed than the orbital rotation is unique in the art of floating concrete. Furthermore, it has been shown how a machine constructed in accordance withthe present invention can have a degree of versatility not contemplated in the art of surface treatment and wherein roller floats of different materials or of. different sizes, or other devices of different structure and uses can be quickly and easily attached to the machine in substitution of rollers or implements that may have been previously installed thereon. It will beapparent to those skilled in the art that the machine shown and'described is exemplary only and that it is obviously susceptible to change in its form, detail construction and arrangement of parts without departing from the scope of the appended claims.

What is claimed is:

1. A rotary power-driven machine for surfacing plastic concrete comprising a vertically positioned rotatable member, a support means, a plurality of horizontally disposed rollers extending radially outwardly of said member and journaled to said support means for rotation about their horizontal axes, each of said rollers having a cylindrical work engaging surface, means for rotatably driving said member and support means to produce an orbital movement of said rollers about the vertical axis of said member, and other means for positively rotating said rollers about their horizontal axes at a greater rate of speed than their natural rolling speed and in the same direction thereof to cause relative movement between the lines of contact between the surfaces of said rollers and the engaged concrete surface.

2. The machine of claim 1 wherein said other means includes pinions coaxially connected to said rollers adjacent said rotatable support means, a relatively stationary ring gear of greater diameter than said pinions, and means for supporting said ring gear coaxially with respect to said vertical member in meshing relationship with said pinions and below a plane through the horizontal axes of said pinions and rollers so as to cause positive rotation of the latter in the same direction but at a greater speed than they would move if naturally rolling on the engaged surface.

3. A rotary power-driven machine for surfacing plastic concrete comprising a vertically positioned rotatable member, a support means, a plurality of horizontally disposed rollers extending radially outwardly of said member and journaled to said support means for rotation about their horizontal axes, each of said rollers having a cylindrical work engaging surface, means for rotatably driving said member and support means to produce an orbital movement of said rollers about the vertical axis of said member, and other means driveably connected to said member for positively rotating said rollers about their horizontal axes at a greater rate of speed than their natural rolling speed and in the same direction thereof to cause relative movement between the lines of contact between the surfaces of said rollers and the engaged concrete surface.

4. A rotary power-driven machine for surfacing plastic concrete comprising a vertically positioned rotatable member, a support means, a plurality of horizontally disposed rollers extending radially outwardly of said member and journaled to said support means for rotation about their horizontal axes, each of said rollers having a cylindrical work engaging surface, means connecting said member and support means, means for rotatably driving said support means to produce an orbital movement of said rollers about the vertical axis of said member, and other means for positively rotating said rollers about their horizontal axes at a greater rate of speed than their natural rolling speed and in the same direction thereof to cause relative movement between the lines of contact between the surfaces of said rollers and the engaged concrete surface.

5. A rotary power-driven machine for surfacing plastic concrete comprising a vertically positioned rotatable member, a support means, a plurality of horizontally disposed rollers extending radially outwardly of said member and journaled to said support means for rotation about their horizontal axes, each of said rollers having a cylindrical work engaging surface, means connecting said member and support means, means for rotatably driving said support means to produce an orbital movement of said rollers about the vertical axis of said member, and other means driveably connected to said member for positively rotating said rollers about their horizontal axes at a greater rate of speed than their natural rolling speed and in the same direction thereof to cause relative movement between the lines of contact between the surfaces of said rollers and the engaged concrete surface.

6. A power-driven surfacing machine for surfacing plastic concrete comprising a rotatable member adapted to be rotated about a vertical axis, a power source operatively connected to said rotatable member for driving the same, support means connected to said rotatable member for rotation therewith, a plurality of horizontal rollers journaled in said support means and extending radially outwardly with respect to the vertical axis of said rotatable member, said rollers having cylindrical work engaging surfaces and being adapted to be moved obitally with respect to said vertical axis upon rotation of said support means, a pinion connected coaxially to each roller adjacent said support means, a stationary ring gear having a greater diameter than said pinions, and means for supporting said ring gear in meshing engagement with said pinions in a horizontal plane below the axes of said pinions and rollers so as to cause positive rotation of the latter in the same direction but at a greater speed than they would move if naturally rolling on an engaged surface.

7. A rotary power driven machine for surfacing plastic concrete comprising a vertically positioned rotatable member, a support means, a plurality of elongated rollers extending radially outwardly of said member and journaled to said support means for rotation about their longitudinal axes, each of said rollers having a work engaging surface providing a horizontal line of contact between said rollers and the surface to be worked, means for rotatably driving said member and support means to produce an orbital movement of said rollers about the vertical axis of said member, and other means for positively rotating said rollers about their longitudinal axes at a greater rate of speed than their natural rolling speed and in the same direction thereof to cause relative movement of said lines of contact between the surfaces of said rollers and the engaged concrete surface.

References Cited in the file of this patent UNITED STATES PATENTS 982,408 Alloway Ian. 24, 1911 1,457,299 Carr June 5, 1923 5 1,566,659 Dutton Dec. 22, 1925 2,288,782 Brown July 7, 1942 2,419,308 Austin Apr. 22, 1947 2,420,876 Freud May 20, 1947 2,468,981 Huffman May 3, 1949 FOREIGN PATENTS 913,884 France June 11, 1946 

